Some examples of applied MEMS include inertial sensors, accelerometers, miniature robots, microengines, locks, micro actuators, optical scanners, fluid pumps, transducers, and chemical, pressure and flow sensors.
MEMS timing and inertial measurement units (TIMUs) are devices used to measure inertial effects and time with a wide range of applications. For example, TIMUs may be used in determining speed, acceleration, and direction, thereby having applications in navigation. MEMS TIMUs can perform the functions of angular rate sensors (gyroscopes), accelerometers, and mechanical oscillators for timers and filters. While discrete sensor and timing units have been successful, integration of several such devices in a single integrated MEMS structure has been met with drawbacks.
For example, silicon structures for timing and inertial measurement devices, including micromachined resonant accelerometers, gyroscopes, capacitive accelerometers and micromechanical resonators for timing units have been tried and tested. In some cases, the conductive properties of silicon have required application scientists to take additional steps to insulate conductors disposed on a silicon substrate.
Some of the drawbacks encountered in previous attempts at integrating a TIMU in a single MEMS structure have been: large size, coupling between devices and the conflicting process and package requirements for accelerometers, gyroscopes, and timing units. System integration is a particular challenge, including the incorporation of temperature control, vibration/shock isolation and sensor fusion.